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221.
Patterning Effect of a Sol-Gel TiO2 Overlayer on the Photocatalytic Activity of a TiO2/SnO2 Bilayer-Type Photocatalyst 总被引:3,自引:0,他引:3
Akihiko Hattori Yoshifumi Tokihisa Hiroaki Tada Noboru Tohge Seishiro Ito Kazutaka Hongo Ryuichi Shiratsuchi Gyoichi Nogami 《Journal of Sol-Gel Science and Technology》2001,22(1-2):53-61
TiO2 films with a thickness of 75 ± 5 nm (anatase) were formed on SnO2-film (580 ± 80 nm) coated soda-lime glass substrates (SnO2/SL-glass) by a sol-gel method. Although the photocatalytic activity for CH3CHO oxidation (ex > 300 nm) significantly exceeded that of a standard TiO2/quartz sample, it decayed with illumination time (t) at t > 0.75 h. Stripes of anatase TiO2 films of 40 nm in thickness and 1 mm in width were prepared on the SnO2/SL-glass substrate in a 1-mm pitch by photolysis of an organically modified sol-gel film. The TiO2 patterning further increased the photocatalytic activity by a factor of 4.1 as compared to the non-patterned sample, and it was also maintained at 0 < t < 2 h. The flat band potentials of the TiO2 and SnO2 films are determined to be –0.34 and +0.07 V (vs. SHE), respectively, at pH = 7 by the Mott-Schottky plots. On the basis of the results, the outstanding patterning effects could be rationalized in terms of the vectorial charge separation at the interface between TiO2 and SnO2. 相似文献
222.
Contamination of industrial sewage by organic dye pollutants is one of the most common challenges to the daily life. Decontamination can be achieved by adsorption and photodegradation of the pollutants. Herein, an effective visible light‐driven photocatalyst of polyoxometalate encapsulated in metal–organic gel was presented. The resulting composite was named PMA@ MOG‐Cr [PMA= H3PMo12O40, MOG= metal‐organic gel]. Photodegradation of dye pollutants with PMA@ MOG‐Cr were tested. The introduction of Phosphomolybdic Acid significantly enhanced the light‐absorption properties of MOG‐Cr. The PMA@MOG‐Cr showed an excellent photodegradation efficiency of MB, RhB and MO as high as 99% and 97% in 60 min and 91% in 120 min of visible‐light irradiation with only 10 mg photocatalyst, which was the highest among the tested samples MOG‐Cr, PMA@ MOG‐Cr and Degussa P‐25. The mechanism of the photodegradation of dye pollutants with H2O2 over PMA@MOG‐Cr under the visible light was further illustrated. The introduction of PMA promotes effective separation of electron–hole pair by trapping and transferring photogenerated electron. Thus, the two components act in synergy to result in much improved adsorption of certain common organic dyes as well as enhanced oxidative degradation. This work provides a new approach to design MOG encapsulated Polyoxometalate for visible light‐induced photodegradation of organic contaminants for the environmental remediation. 相似文献
223.
Gamma Ray Radiation Effect on \begin{document}$\rm{{Bi}}_{2}$\end{document} W\begin{document}$\rm{{O}}_{6}$\end{document} Photocatalyst 下载免费PDF全文
The development of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} -based materials has become one of research hotspots due to the increasing demands on high-efficient photocatalyst responding to visible light. In this work, the effect of high energy radiation (\begin{document}$\gamma$\end{document} -ray) on the structure and the photocatalytic activity of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} nanocrystals was first studied. No morphological change of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} nanocrystals was observed by SEM under \begin{document}$\gamma$\end{document} -ray radiation. However, the XRD spectra of the irradiated \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} nanocrystals showed the characteristic 2\begin{document}$\theta$\end{document} of (113) plane shifts slightly from 28.37\begin{document}$^{\rm{o}}$\end{document} to 28.45\begin{document}$^{\rm{o}}$\end{document} with the increase of the absorbed dose, confirming the change in the crystal structure of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} . The XPS results proved the crystal structure change was originated from the generation of oxygen vacancy defects under high-dose radiation. The photocatalytic activity of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} on the decomposition of methylene blue (MB) in water under visible light increases gradually with the increase of absorbed dose. Moreover, the improved photocatalytic performance of the irradiated \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} nanocrystals remained after three cycles of photocatalysis, indicating a good stability of the created oxygen vacancy defects. This work gives a new simple way to improve photocatalytic performance of \begin{document}$\rm{Bi}_2$\end{document} W\begin{document}$\rm{O}_6$\end{document} through creating oxygen vacancy defects in the crystal structure by \begin{document}$\gamma$\end{document} -ray radiation. 相似文献
224.
《Arabian Journal of Chemistry》2022,15(4):103729
In this study, a ternary TiO2/g-C3N4/Bi2WO6 nanocomposite was prepared via a facial approach. The final structure was applied as a new photocatalyst for the removal of brilliant green (BG) dye, as a model of organic pollutants, from the aqueous solution. The results of FESEM, EDS with mapping, XRD, FTIR, UV–vis DRS, PL, and EIS analyses further demonstrate the successful establishment of heterojunction between TiO2, g-C3N4, and Bi2WO6. Integration of g-C3N4 and Bi2WO6 with TiO2 was remarkably decreased the band gap energy of TiO2 to 2.68 eV (from 3.15 eV). The effects of various experimental factors such as TiO2/g-C3N4/Bi2WO6 dosage, initial BG concentration, visible irradiation time, and pH on the photocatalyst behavior of TiO2/g-C3N4/Bi2WO6 were investigated by 2 k-1 factorial design. The results of the analysis of variance demonstrate these experimental factors are effective on the BG degradation efficiency. The response surface methodology was applied to achieve the optimization procedure of BG degradation. According to these results, the complete BG removal efficiency was obtained for the optimal conditions of 15.76 mg of TiO2/g-C3N4/Bi2WO6 nanocomposite, an initial BG concentration of 10 ppm, pH of 9, and time duration of 70 min. The improved photocatalytic performance of ternary TiO2/g-C3N4/Bi2WO6 nanocomposite was related to the formation of heterojunction between TiO2, g-C3N4, and Bi2WO6, significant light adsorption ability, and low recombination of photogenerated carriers. 相似文献
225.
TiO2/AC复合光催化剂对苯和丁醛的气相光催化降解机理 总被引:1,自引:0,他引:1
利用溶胶-凝胶并水热处理法制备了TiO2光催化剂和TiO2/AC复合光催化剂,在静态光催化反应器中研究了苯和丁醛的气相吸附和光催化降解,利气相色谱分析确定了生成的中间体. 结果表明, TiO2/AC复合光催化剂比TiO2光催化剂具有较强的吸附能力和较高的光催化活性; 在TiO2和TiO2/AC上,苯(或丁醛)光催化降解产生相同的中间体,表明在两种催化剂上发生的光催化反应遵循相同的机理,进而讨论了其可能的光催化氧化途径. 相似文献
226.
227.
Avinash S. Bansode Supriya More S. V. Bhoraskar V. L. Mathe 《Surface and interface analysis : SIA》2015,47(1):22-29
The paper presents an improved method of depositing nanocrystalline thin films of Fe‐doped TiO2 to be used as a reusable cyclic photocatalyst for degrading the organic pollutants. The technique of electron cyclotron resonance plasma‐enhanced chemical vapor deposition was employed with titanium tetra‐isopropoxide (C12H28O4Ti) and ferrocene (C10H10Fe) as precursors of Ti and Fe, respectively. Optical emission spectroscopy was used to identify the reactive species, to determine the electron temperature and the ion density during deposition. The films were characterized using optical absorption and photoluminescence spectra, whereas the morphological analysis was carried out with scanning electron microscopy. Strong adhesion of the deposited films with the substrate ruled out any possibility of TiO2 particles being leached out. It was confirmed by observing the degradation rate of the same film repeatedly. Cyclic use of the film for the catalytic reactions thus makes the process much user friendly for the water treatment. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
228.
合成了2,9-二甲基-1,10-邻菲罗啉的铀(Ⅵ)超分子杂化配合物[UO2Cl4]2[dmphenH2]2·3H2O(1),并进行了IR、UV、XPS和X单晶衍射分析。 铀的杂化配合物呈六配位的变形八面体结构,属单斜晶系,Cc空间群;晶胞参数分别为:a=1.7043(2) nm,b=0.8809(13) nm,c=2.7492(10) nm,α=90°,β=94.493(2)°,γ=90°,Z=4,V=4.1149(8) nm3。 氢键和π…π相互作用大大加强了配合物的稳定性。 配位导致紫外光谱的最大吸收峰发生红移。 荧光光谱显示,配合物在407 nm的光激发下可发射506.6 nm绿色荧光。 电化学研究表明,该配合物具有一对可逆的氧化还原峰和一个不可逆的还原峰。 该配合物在紫外光照射下显示出极高的光催化活性。 CCDC:780721 相似文献
229.
纳米V2O5/ZnO光催化剂对壬基酚聚氧乙烯醚降解的催化活性 总被引:2,自引:0,他引:2
采用氨浸法制备了不同V2O5含量的纳米V2O5/ZnO光催化剂,并用X射线衍射、比表面积测定、透射电镜、X射线光电子能谱和漫反射紫外-可见光谱测定了催化剂的晶型、比表面积、形貌尺寸、表面组成和光谱特征.以壬基酚聚氧乙烯醚(NPE-10)为模型污染物,分别在紫外光和可见光照射下考察了光催化剂的催化活性.结果表明,随着V2O5含量的增加,V2O5/ZnO的粒径逐渐减小,比表面积逐渐增大.与纳米ZnO样品相比,V2O5/ZnO中V2p的结合能减小,而Zn2p和O1s的结合能增大,V2O5/ZnO表面的羟基氧和吸附氧含量增加.n(V)/n(Zn)=2·5%的V2O5/ZnO光催化剂样品的催化活性最高(在紫外光和可见光照射3h后,NPE-10降解率分别约为79%和62%). 相似文献
230.
溴氧化铋(BiOBr)半导体已被应用于光催化CO2还原,但其活性仍然极低。通过简单的水热法合成了Zn-BiOBr光催化剂,并在可见光照射下研究其对CO2催化效果。结果表明,合成的Zn-BiOBr样品在可见光照射下具有比原BiOBr更高的光催化还原CO2转化活性,其对CO2光催化还原速率最高可达到8.49 μmol·h-1,是原BiOBr的13倍。同时,我们亦对光催化活性增强机理进行了研究,发现在可见光照射下,Zn-BiOBr半导体被激发,产生光致电子空穴对,光诱导电子有效还原CO2,生成CO。锌的掺杂为BiOBr提供了更合适的带边位置和能带缺陷,降低了光生电子与空穴对的复合速率,大大提高了光催化还原CO2的能力。 相似文献